Distillation



May 28, 4

c, PERNER bisTILLATIoN Filed June 29. 1945 2 Sheets-Sheet 1 nvvE/vruR johw 6! PERNERT,

ATTORNEY May 28; 1946.

J. c. PERNERT DISTILLATION Filed June 29, 1943 2 Sheets-Sheet 2 F I G. 6. INVENTOR.

JOHN c. PERNERT,

ATTORNEY Patented May 28, 1946 ms'rmm'rron John 0. Pernert, Niagara mam. Y., assilnor to Oldbury Electro-Chemical 00., N. Y., a corporation of New York Application June 2a, 1943, Serial No. 492,696

2 Claims This invention relates to the art of distilling and to the selective condensation and recovery of'a purified vaporized volatile component of a complex or mixed liquid material to be so treated.

One object of the invention is to recover from a liquid material having a plurality of volatile components, at least one such component in purilied and condensed form. Another object is to devise a combined vaporizing and condensing apparatus whose operation is continuous and substantially automatic so that it requires a minifurther object is to devise such an apparatus wherein either 'or both of the feeding and discharging operations maybe carried out at atmospheric'pressure. A still further object is to devise such an apparatus wherein its selectivity is accurately controllable. Another object is to devise such anapparatuswherein the concentration of the yielded desired condensate is controllable. And another object is to devise such an apparatus wherein non-volatile impurities residual in the still are readily, if not auto-, matically, removable therefrom. A

The invention may be said to comprise a conduit having a boiler or vaporizersection and one or more condenser sections with means for maintaining a substantially predetermined temperature .and pressure in each, coupled with pump means for effecting suction in the conduit and its sections, together with means for maintaining a body of liquid to be treated withinthe vaporizer, and means for collecting a body of condensate from one or more of the condensers. The invention also comprises process steps as well as combinations thereof which may be carried out in this or other apparatus.

Another feature of the invention comprises the use of a barometric leg dipping into a pool of mixed or complex liquid material at atmospheric pressure to be treated wherein the barometric leg maintains a body of such liquid extending into the vaporizer to a substantially constant leveltherein. Another feature comprisesautomatic controliof the rate of feed. A further feature comprises the use of a barometric leg for collecting condensate from a condenser and dipping into a pool of yielded liquid. with the pool existing at atmospheric pressure. And a further feature comprises maintaining sub-atmospheric pressure in the conduit.

The complex or mixed liquid material for-the treatment of which the apparatus of this invenmm of attendants. Yet another object is to devise such an apparatus-that is self feeding; A

tion 'is designed, comprises least two volatile components with differential vaporizing temperatures, and with or'iwithout adapted to hold a non-volatile components of which one or more may be in solid phase. Illustrations oflsuchcomplex or mixed liquors include impure reaction products such as butyloxalate; tributyl phos-v phite', perchloric acidrand the like. "A specific example of the latter is disolosedin myco-pending patent application Serial No. 487,498. r i

The invention is illustrated in the accompany-' ing drawings whichshow a preferred ernbodi ment thereof that is given solely to facilitate an understanding of the inventio since this show-v ing is not to be considered as limiting, for obviously the invention maybe practiced in differing apparatus, or in differing parts thereof, because this invention resides inits parts as well as in combinations thereof, as 'can' be judged; from the;

appended claims.

In the drawings. F re connection with one or "both of the hotfl con' densersHC'andH "-qv v 7 Referring to Figure 1,1 the distilling system of this invention begins with atankorbasin ill pool of starting. complex or mixed liquid material or liquor [2. into which dips a barometric leg l3 adapted tojholdfai columnor body of liquid it maintained up toalevel 18, to;

be treated in the boiler 'oif vaporiaer-section'vt q is a part of the general conduit .23, Thevaporizerv V is comprised of an outercasing lor steam Jacket It that encircles a part'for portion i'iof the con-., duit 22 and is" provided lwithifla" steam in t: and a steam outlet li adaptedtosupplysteani to the steam space 20 that lies between the. part, il of the'conduit f r a jacket l6. vaporization. takfes' piooew tmn; the portion ll of the conduit 22 so "itisi a apoi'izing zonea. i.

That art of the general conduit n, after from the vaporizer vrisprovided with a trap z;

onquid having at 1 shows anl isometricview of the ap aratus of this invention, with some parts broken away to show interior construction; and some parts shown only diagrammaticallyffl Fig. 2 is an enlarged viewQwith parts broken away, of the vacuum regulator I9 ofFigil Fig. 3 shows a detail of construction thereof;llFig.j--i is a detail view of the vacuum indicatorgr Figib 22. andjthe oute eas ng;

cold condenser zone.

Kieldahl bulb. about as shown The conduit then reaches 'ahighpoint 22' from whence it descends to be provided with a hot condenser,

indicated generally by the letters HC", and comprises an outer casing or jacket 25 that encircles a part or portion 26 of the conduit 22 to provide between it and the jacket 25 a space. 21 to whichhot water may be supplied through inlet 28 and removed through outlet 24; Portion 26 of conduit 22 thus comprises a hot condenser zone.

The general conduit 22 then continues through an extension 29 that. joins a barometric leg 3| which dips into .a pool of liquid 34 held in a .2 scope? It a to be-noted that the mum level L of jar or basins; having a discharge spout 22.'

liquids, although normally I prefer two in order to provide better or more eflicient control. From HC", conduit 22 rises through an extension 36 to join another barometric leg 46 dipping into a pool of liquid 44 contained in a basin #3 having a discharge spout 42. Leg 46 is adapted to the body of liquid 80in barometric leg 3! is maintained at a level below the extension 29 of conduit 22 so that liquid of the body is unlikely to pass, or to be, passed, backward into the hot condenser HC'.

Somewhat similarly, the liquid level L of the liquid body ll, of barometric leg 40 is maintained at a level below the extension .39 of conduit 22 so that liquid of the body is unlikely to pass, or to be passed, backward and down into the hot condenser H And again, the body of liquid 58 in'barometrlc leg 51 has its liquid level L? maintained at a level below the extension 56 of conduit 22 so that liquid of the body is unlikely to. pass, or to be passed, backward into the first cold condenser CC. Also, it is to be observed that the barohold a column or body or liquid 6! which rises to a level about at t e point L.

Conduit 22 then esthrough an intermediate condenser unit IC comprising an outer casing or jacket 46 encircling a portion 41 of the conduit 22, providing therebetween a water space R to which water is supplied through inlet 46 and discharged through outlet 49. Portion 41 of conduit 22 is thu an intermediate condenser zone.

Conduit :22 then rises to a high point 22 and descends through a cold condenser unit CC comprising an outer casing or jacket v52 encircling a portion 5L0! the conduit 22, providing therebetween a water space 54 to which water is supplied through inlet 55 and discharged through outlet 5|. Portion 63 of conduit 22 is thus a Conduit 22 then descends to Join an extension 66 connected to a further barometric leg 61 adapted to hold a column or body of liquid 58, maintained to extend to a liquid level about at L". Barometric leg 67 dips into a pool of a liquid 69 held in any suitable basin or the like 60, having a spout 6| and possibly another outlet 62.

Conduit 22 next rises through another cold condenser unit CC" comprised 01' an outer casing or jacket 64 encircling a portion 66 or conduit 22 to provide a water space 86 therebe-.

tween, to which is supplied cooling water through inlet 63 and discharged through outlet 61.

From this cold condenser CC", the conduit .22

rises to a dome-like end 10, just below which are two nipple connections II and 12 respectively;

metric leg 3| is arranged to collect distillate from both hot condensers HC' and H and, indeed, it 'is such'condensed distillate that forms the body of liquid 30 in that leg. Similarly, barometric -leg 46 is adapted to collect condensate from intermediate condenser 10 and such condensate forms the body of liquid 4| therein. Also barometric leg 61 is adapted to receive and collect condensate from the cold condensers. CC'and CC". i

In the embodiment of the perchloric acid still shown, the conduit 22 and the barometric legs are made of blown glass tubing two inches in vdiameter, whereas the jackets of the vaporizer and condensers are of steel, with suitable sealing connections and packing glands between them and the glass tubing of the conduit. The length of vthe vaporizer and the condensers, as well as their relative disposition as to height, is indicated generally in Fig. 1 by the more or less' accurate scale in feet shown in that figure. In order to get the proper length of the barometric leg 61 in the installation illustrated, the pool of 1 liquid]! in the basin or bottle is located beneath the floor 80. This still rises to a height of 45 feet or so, and of course'must have some supporting structure to sustain it, but no such structure has been shown in the drawings because such structure forms no part oi this invention.

, ing except as specifically set forth herein.

A brief description of the operation of the apparatus is that the vacuum producer or suction device or pump I6 effects a suction on the entire length or the conduit 22, through vaporizer V, through hot condensers HC' and HC", through intermediate condenser IC and through cold condensers CC and CC, to the vacuum pump. This suction holds the liquid body ll sucked from the pool of liquid l2 (which is to be distilled), in barometric leg it up to its desired level; holds liquid body 80. in barometric leg ll up'to its desired level; holds'liquid body in barometric leg 40 up to its desired level-and also sucks (a) vapors from the vaporizer V into the hot condenser HO"; (1)) vapors escapingfrom the latter into the hot condenser H (c) vapors escaping therefrom into the intermediate condenser; (11) vapors escaping therefrom into first cold condenser CO: (e) vapors escaping therefrom into the second coldcondenser CC"; and finally (I) any vapors still escaping into' the pump 18 to discard. I

The liquid material l2 or tank II which is to be distilled has, from the standpoint of the distillation process, at least two predetermined or significant volatile components with difierential condensing temperatures, so when these volatile components are vaporized in the vaporizer V, their vapors pass through hot condensers HC' and H which are maintained heated to a temperature whereat there condenses a major portion of the vaporized primary component which has the higher condensation temperature, while in general the other or others do not. If the condensation temperatures of the two significant components are near together, naturally more of the secondary component may become inadvertently condensed here than otherwise, but its quantity can be minimized by careful control, as hereinafter explained. Distillate comprising the condensed primary component flows into and collects in. the leg 8|, while the yet vaporized and lects in the leg 48 and basin 48. Vapors escaping condensation'in the intermediate condenser IC are sucked to the cold condensers which are maintained at a still lower temperature wherein the remaining components are condensed.

The result of this. operation is that primary or significant distillate is recovered in concentrated condition from the hot condensers HC'and H through the barometric leg 8| and the pool 84 in basin 88. This distillate has the highest concentration and the least contamination, as compared with the condensate recovered from the intermediate condenser 10 through barometric leg 48 and the pool 44 in basin 48. For this reason, the condensate from the hot condensers, recovered from barometic leg M will be sometimes referred to as distillate while the condensed fraction from the intermediate condenser will be referredto as condensate-and so will the condensate from the cold condensers that is collected in barometric leg 81, because these condensates have so much more dilution or other contamination that they do not compare with the primary and significant .end product distillate 84. I

The controllable selective fractional or sequential condensation of a plurality of volatile components vaporized in one vaporizer zone, is an important feature of this invention, especially when carried out continuously. For obtaining careful and possibly critical control of the selective fractional condensation carried out, the hot 'condenseror condensers of this invention play an important part, namely, the pressure and temperature thereof must be accurately controlled and correlated. That is, it is desirable to have the vacuum or suction automatically end I88. The U-tube contains mercury having maintained substantially constant in the entire toadmitair as required when the-vacuum be-' comes too great, and thus operates as a control nechanism in association with the vacuum pump More particularly, the flexible tubing 10 attached to nipple I2 is connected to an inlet pipe 81 leading to the main body portion 88 of the manometer, having a dome 88 supporting a tubular-extension 84 rising from within the body of the manometer. This extension 84 terminates in a valve seat 82 into which fits a valve 8| from which depends a steel wire 88 extending downwardly through the tube 84 and supporting a float 88, preferably of; hard rubber, which is adapted to rest on a. column or leg of mercury 88 having a liquid level 88. The main or primary body 88 or the manometer is connected by a.

U-tube 8! with a secondary body 82 of the manometer, sealed from the atmosphere as at 88 and adapted to hold anotherleg orcolumnof mercury 88 which balances the leg of mercury 88 in the primary body 88. The leg 88 has a liquid level 84.

In operation, so long as the suction or vacuum in the conduit system 22 is of correct degree, the mercury leg 88 stands in equilibrium with leg 88 with its. level 88 as shown, on which float 88 floats, and valve 8| is seated on its valve seat 82, meanwhile conditions continue constant. But if the vacuum or suction is increased in degree by the pump 18, more than is desired, mercury leg 88 is sucked upwardly so that its liquid level 88 rises, which in turn lifts float -88, which in turn unseats valve 8| and allows air to enter. the system through pipe 81,

and tubing 18 into the conduit system 22, whereupon the degree of vacuum is lessened. As soon as enough air has been- ;admitted to restorethe system to its proper aub pressure," valve ;8l is seated automatically and no more airis admitted until vacuum pump 18 has again reduced the subpressure to the value at which the regulator will In the tubing 18 connected with nipple II is a vacuum indicator indicated generally at 14 which may comprise, as shown in Fig. 4, a U- tube having one leg- I88 connected with tubing 18 and anotherconnecting leg 88 sealed at its one column 88 inleg. I88 with a. liquid level I84, and another column of mercury 81 in leg 88 having a liquid level 88. Thediiferential heights of these two columns of mercury indicatesthe amount of vacuum existing in the conduit system 22 measured in inches of mercurynamely the liquid level I84.

Since the maintenance of substantially constant temperature in the hot condenser is about as important as the maintenance of constant vacuum onthe conduit system 22, Fig. 6 shows a preferred embodiment of accomplishing this eflect.

In Fig. 6 a typical hot condenser HC' is shown withits jacket 28 having a hot water inlet", (at the a bottom) and a hot water 'outlet 24 at the top.;. Between thisinlet and outlet isa pre-' ferred embodiment of awater heating and temperature control system shown diagrtically and comprised as follows: Water passes'from outlet 14 through piping I65 to a water storage tank I06 from which water may be withdrawn through pipe I91 that is controlled by valve I88, by a circulating pump I09, and passed to a .water heater H0, from which heated water passes through pipe HI controlled by valve H2 to hot water inlet 28 of the jacket 25 of the hot con denser HC'. To the water heater H is supplied thereof, have been observed to descend in the liquid column it of barometric leg I8 and collect in pool I2 in the basin II, from which they can be removed readily, without the necessity of even interrupting the distilling process. The mixed or complex vapors pass on. due tothe suction of the pump I5, to the hot condenser HC'.

'- It is commonly, if .not usually, observed that in distillations a relatively small proportion ofsteam through pipe II! having a suitable valve control lit, adapted to supply the'heat to the water in the heater IIIi. Exhaust steam is conducted from the heater through pipe H5. In steam pipe line H3 may be placed a temperature regulator 6 which is connected by a circuit.

II! to a, thermostat at about H8 in the hot water line. If the temperature of the water passing into the jacket is too-low, the thermostat H8 operates the regulator H6 to feed more steam to the heater H0 and vice versa. This temperature control system for the heating water, of course, can, and in the preferred form does, operate for both hot condensers. The heating system is a closed one so that water temperatures above 100 C. can be used. Also heating media of other than steam and water may 'also be used.

The vaporizer V of this invention is another highly important element thereof, so it has been shown in enlarged detail in Fig. wherein it so shows that the barometric leg I3 dips intov a pool I2 of liquid to be distilled, held in basin ll. Suction from the vacuum pump I5 causes liquid from the pool I2 to rise in the barometric leg in a body non-volatile residue is not removed automatically 'as described due to its adhesion to the heated the apparatus of Fig. 6, to be such that it is above the condensation point of .all but that of the primary significant volatile component of the liquid being distilled, which is desired to be recovered in concentrated and distilled form as the end product of the distillation process. This component is condensed and becomes the distillate that is collected in the barometric leg 8| and forms a body or column of liquid .30 therein that finds its way into the pool 34 in basin 33 whence itis recovered at atmospheric pressure. In some cases, a single or column i4 and extend to a height so that it 85 hot condenser HC' will be sufiicient, but in cases has a liquid level I8 maintainedwell within the vaporizer zone within the jacket it around portion I! of the conduit 22. Heating steam is let into the jacket at 2i and out at I5 to maintain the where it is doubly important that the end product shall be highly concentrated, the second hot condenser HC" can be used for further selectively or fractionally condensing any vapors of the prip 20118 at temperature above the Vapormary or major significant volatile component izing temperature of the significant volatile components of the liquid to be distilled. Vapors therefrom are sucked from the liquid level I8 as shown by the arrows, due to the suction created by the pump I5. Non-volatilized spray and solids are entrapped in the Kjeldahl bulb 23 or other suitable trap, and tend to descend therefrom and ultimately settle into the pool l2 of the basin II, from where they can be removed to discard.

The length of. the barometric leg I3 and the degree of suction, or vacuum, are correlated so that the liquid level It is maintained well within the vaporizing zone- V, which means that this vaporizer is self-feeding. The temperature of the zone is maintained so that all of the volatile components of the liquid to be distilled, or particularly the significant two or more, are simultaneously vaporized in order to produce the complex or mixed vapors that are to be selectively condensed later in the hotcondensers and the intermediate condenser. This vaporizer has a further advantage of being automatically self-cleaning in that residual deposits of solids that normally are retained within the vaporizing zone (1. e. in the conventional type of still-a distilling flask for instance), and form a "still residue tend, in this to the removal of volatile solvents from solutions that may somehow have escaped condensation in the first hot condenser HC'. densed to become distillate, it is collected in the same barometric leg 3i as described for hot condenser HC'.

Vapors sucked from the hot condenser HC", which have escaped being condensed therein, pass to the intermediate condenser 10 wherein a temdensate is collected in the barometric leg 40 as a column or body of liquid ll that finds its way downwardly into the pool I! of basin 43 whence it can be removed readily. This condensate liquid jllcan be used or not as the case may be. Any vapors escaping condensation in the intermediate condenser IC are sucked onwardly into the cold condenser CC and these normally comprise the volatile second significant component and possibly others of the liquid to be distilled. Such condensate maybe discarded, if of no value, or it may be used if it contains valuable constituents.

Since the condensation point of vapors involves the correlation of the two factors of pressure and temperature, both must be taken into consideration in the operation of the condensing zones of this still. Ordinarily, that degree of when S0 conw re at or rather'oi vacu is chosm r- N temperature or the :1 "6 omponents tothe desired degree and teases beca it must be siimcient to sucs'uie liuid to bewaporizedinto thevaporizei' V and the vapors thereirornonwardly through the successive condenser zones. So some suitable vacuum is selected, whereupon the temperaturewhereat the components will vaporize at the selected subp can then-be determined. and this will be the temperature for the vaporizing zone; suitable temperatures for each of the con 1 denser zones may also be selected, but these may require subsequent adjustment to attain highest eiilciency and at the sometime the desired concentration of the endproduct. Thereafter the mu-oi, apparatus for-n aintaining the suction, and for maintaining the temperatures in the condensers but especially the hot next be set into operation.

The attendant then needs only condenser, can

to see that the operation; oithe stillis proceeding smoothly and flcontinuously. samples can be taken occasionally of the liquid yielded in the pool it of basin 33 from the hot condenser EC to make sure that it has the correct 9 concentration and minimizaincorrect, then adjustment is made either in the temperature or in the suction, as seems preferable,or'possibl'y a slight adjustment of both. In

71 the casefoi distilling perchloric acid from a reaction product starting material, it has been possible to recoverl concentrated distilled perchloric acid from the hot condenser such that it has less than 5 parts per million non-volatiles in it and les'sthanl part per" million of iron. The concentration of such distilled acid'has been attained that lies fbetween'lo and:'72%. A yield of such "acid hasrbeemobtained.irom the first hot condenser HC' that; comprises as much as 90% of the available-H0104, using vacuum in the con- .duitlz equa'l to /4 inch of mercury and mainataining the-temperature in the hot condenser in 12a, rangeoi iromi 90 ,C. to 91 C. with the average --standingat aboutv patent application,

therdetailsJ Examples of the 93 C. (See my copending distilling, by the yuseof-this invention; of other complex or mixed liquorsiollowz 5 mi I "-Drsrn.r.Arron or 1m Esra-n '1, new oxalate i lmpureidibutyl oxalate prepared by a conventionalamethod', viz.;.boiling oxalic acid with nbutyl alcohol (commercial butanol) with provi- -L sion for allowingthe 'escape of water contained 5 in the reactants and formed during the reaction 1 resulted inthe production of a mixture containzii'ing about 80% dibutyl oxalate and unreacted butanol along-with volatile and non-volatile im- 7 "purities. Distillation proceeded according to this :finvention and, was to obtain substantially purifled dibutyl oxalate nearly free non-volatile impurities.

Hot condenser temperature..- Cold condenser temperatures. 5 0. Pressure 1.0" of mercury measured by a manometer. At 1" of Hg pressure pure dibutyl oxalate boils at slightly over 140 0., while butanol bolls well under 95 C. The hot condenser, therefore, condensed ester and little or no butanol. The cold. condenser condensed most or the butanol and most oi the ester not condensed in the hot condenser.

oi volatile and serial No. 487,498, for 1111.

tity oi conemanates and-arr densatewasrernoved were ed; their 8p. g. at' Refractive 1 0. index The-two condensates were clear and colorless while the undistilled residue was colored and somewhat turbid. This indicates that the distillate was substantially purified with respect to non-volatile material. The condensate from the hot condenser had no odor of butanol, and-its physical properties were approximately the same tion of contamination. If these properties are as those of dibutyl oxalate known to be pure.

, This indicates substantial purity of this condensate. The cold condenser condensate was a mixture containing about A; dibutyl oxalate and about n-butyl alcohol, also possibly some volatile impurities.

M. II-Drsmtsnon or are ESTER T itium phosphite Commercial butanol was reacted with phosphorus trichlor'ide producing a reaction product containing tributyl phosphite. The reaction mixture contained about 20% unreacted n-butyl alcohol, a large percentage of tributyl phosphite and, as an impurity, butyl acid phosphite along with other reaction products and impurities. Partial removal of acidic impurities was accomplished by adding an excess of anhydrous ammonia and filtering. The material requiring distillation contained around 80% tributyl phosphite, the desired product, and around 20% butyl alcohol along with impurities such as butyl chloride, ammonia, etc. (volatile) and ammonium salts I (relatively non-volatile).

The mixture was distilled as described in Extilled residue, colored and somewhat turbid. Thehot condenser condensate had a very faint odor, but was substantially purified tributyl phosphite. It was slightly acidic, and this indicates that it may have contained a small amount of an acidic ester as an impurity, possibly dibutyl phosphite. The cold condenser condensate contained about 75 to 80% n-butyl alcohol, the remainder largely tributyl phosphite along with some volatile impurities.

Exams: III-momma A Sorvmr Butfll Cellosolve Commercial monobutyl ether or ethylene glycol,

butyl Cellosolve, 0439002114011. was found valuable as a solvent 10: purification or certain salts condenser." i physical properties are shown in thetable below:

' Water about '5 ,C. A quantity was vacuum distilled in the apparatus and by the procedure described in Example I.

Vacuum of Hg. Hot condenser temp 85 C. Coldcondenser temp. 5 C.

After a period of distillation during which solution was fed into the vaporizing zone continuously while heat was applied so that the mixture boiled vigorously and distilled, the condensates from the hot.v and cold condensers were examined:

' Percent Condensate from hot condenser butyl Cellosolve' 9'1 Water 3 Condensate from cold condenser butyl Cellosolv v The condensate from the hot condenser was suitable for re-use in purification ofv further quantities of salt.

-EX;AHPLE IV-PERCHLORIC ACID Impure perchloric acid was made by reacting an excess of concentrated hydrochloric acid with a warm, saturated solution of sodium perchlorate. The mixture was cooled and the solid phase (principally NaCl) was removed by filtration. Most of the HCl, and a part of the water was removed by evaporating the solution until it contained about 57% HClOa The solution was allowed to cool whereupon solids" crystallized and settled out.

The clear, supernatant liquor decanted from the solids was used in the subsequent distillation. It had the foliowing compositiom- HC104956 8. p.1 per cent..

The condensate from the hot condenser was practically colorless and contained 70.3% of perchloric acid. The non-volatile impurities were less than 50 parts per million: HCl was about 1 P. P. M.

The condensate from the cold condenser con- I tained about 88% H20, 11% HC104, a small amount of HCl, and was pale yellow in color.

The residual, undistilled material was colorless, and contained a large proportion of solids (nearly all crystallineNaCloi) which settled readily when boiling had ceased.

l. Distilling apparatus comprising aconduit having avaporizer section and a condenser section, a barometric leg for each of said sections with the leg of the vaporizer section being substantially uniform in diameter therewith, a supply of mixed feed liquor in a pool into which dips the leg of the vaporizer and which has at least two significant componentswith diflerential con- HCl-O.5 g. p. 1 do 0.03 Non-volatile 26 g. p. l. ....do 1.6 Water (by'diflerence) --do. 38.37. Sp. g 1.60

This mixture was distilled as described in Example I:

Hot condenser temperature 99 C. Cold condenser temperature 5 C. Pressure 1.0" (25 mm.) Hg

its temperature was automatically maintained at 99 to 100 C.

densing temperatures, fluid jacket means external of the vaporizer for controlling the temperature of the contents of the vaporizer to be at least at the vaporizing temperature of both saidcomponents, means external of the condenser for controlling the temperature of the contents thereof to be below the condensing temperature of one but above that of the other vaporized components, a basin ,for collecting condensate from the condenser passing thereto through the leg of the condenser, and automatically controlled suction means for maintaining sub-atmospheric pressure in the conduit to a degree tof suck feed liquor from the pool .upwardly into the vaporizer through its leg and to maintain liquor so sucked into the vaporizer at a level therein between the bottom and top thereof, said vaporizer being at an elevation directly above the leg withthe leg forming.

a downward continuation thereof sufiiciently vertical for gravitational settling ofsuspended solids from the vaporizer to the leg with the leg thus simultaneouslyiorming not only a path for the taining in association with each said condenser means a single body of liquid derived from vapors condensed therein.

. JOHN C. 'PERNERT. 

